This invention relates to a method of welding a circuit conductor and a terminal of a control apparatus having a plurality of terminals by melting and joining by a welding arc.
U.S. Patent Application Publication No. 2008-102716 (corresponding to Japanese Patent Application Publication No. 2008-110357) discloses a welding method of welding, by a resistance welding, a terminal of an FET (field effect transistor) and a bus bar which is a circuit conductor used in an EPS (electromotive power steering device) control unit. That is, in general, in the EPS control unit, the FET is soldered to a glass epoxy substrate (board), or the FET is soldered to a metal substrate (board). Moreover, in general, a projection is provided to the terminal of the FET, and the FET is joined to the bus bar and so on by the resistance welding. In an arc welding, the too large current flows at the welding, and too large current may break the electronic component. Accordingly, the arc welding is infrequently-used.